[26/63] dyndbg-test: change do_prints testpoint to accept a loopct

Commit Message

Jim Cromie Jan. 25, 2025, 6:45 a.m. UTC

echo 1000 > /sys/module/test_dynamic_debug/parameters/do_prints

This allows its use as a scriptable load generator, to generate
dynamic-prefix-emits for flag combinations vs undecorated printks.
This will make it easy to assess the cost of the prefixing.

NB: the count is an unsigned int, and is *not* clamped currently, but
probably should be.

Signed-off-by: Jim Cromie <[e-mail]>
---
 lib/test_dynamic_debug.c | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

Patch

diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 74b98adc4ed0..5cfc156ca4bb 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -16,16 +16,24 @@ 
 
 /* re-gen output by reading or writing sysfs node: do_prints */
 
-static void do_prints(void); /* device under test */
+static void do_prints(unsigned int); /* device under test */
 static int param_set_do_prints(const char *instr, const struct kernel_param *kp)
 {
-	do_prints();
+	int rc;
+	unsigned int ct;
+
+	rc = kstrtouint(instr, 0, &ct);
+	if (rc) {
+		pr_err("expecting numeric input, using 1 instead\n");
+		ct = 1;
+	}
+	do_prints(ct);
 	return 0;
 }
 static int param_get_do_prints(char *buffer, const struct kernel_param *kp)
 {
-	do_prints();
-	return scnprintf(buffer, PAGE_SIZE, "did do_prints\n");
+	do_prints(1);
+	return scnprintf(buffer, PAGE_SIZE, "did 1 do_prints\n");
 }
 static const struct kernel_param_ops param_ops_do_prints = {
 	.set = param_set_do_prints,
@@ -177,17 +185,20 @@  static void do_levels(void)
 	prdbg(V7);
 }
 
-static void do_prints(void)
+static void do_prints(unsigned int ct)
 {
-	pr_debug("do_prints:\n");
-	do_cats();
-	do_levels();
+	/* maybe clamp this */
+	pr_debug("do-prints %d times:\n", ct);
+	for (; ct; ct--) {
+		do_cats();
+		do_levels();
+	}
 }
 
 static int __init test_dynamic_debug_init(void)
 {
 	pr_debug("init start\n");
-	do_prints();
+	do_prints(1);
 	pr_debug("init done\n");
 	return 0;
 }